1. Field of the Invention
The present invention relates to a sheet package in which a stack of a plurality of folded sheets is packaged in a receptacle having a dispensing opening in such a manner as to continuously dispense the sheets.
2. Prior Art
Wet sheets are used for cleaning hands, for wiping babies"" crotches or for wiping or cleaning toilets or kitchens. In order to maintain the sheets in a wet state, they are airtightly packaged in a container such as a hard case or a bag made of a package sheet. In this container, there is formed a dispensing opening for allowing the sheets to be sequentially taken out. The wet sheets of this type are stacked vertically one on top of the other in an interfolded manner. Accordingly, when an overlying sheet is withdrawn through the opening of the container, an underlying sheet is lifted and drawn to present an upper portion thereof in a readily accessible location above the opening.
FIG. 7 is an illustration of the conventional pop-up type of sheet package as set forth above.
In the sheet package shown in FIG. 7, a plurality of folded wet sheets 101 are stacked vertically one on top of the other in an interfolded manner. Each of these wet sheets 101 is folded in a Z-configuration to define a top flap portion 104 folded upward upon a central portion 103 and a bottom flap portion 102 folded downward under the central portion 103.
In the relationship between overlying and underlying wet sheets 101, the top flap portion 104 of the underlying sheet 101 lies between the bottom flap portion 102 and the central portion 103 of the overlying sheet 101. The bottom flap portion 102 of the overlying sheet and the top flap portion 104 of the underlying sheet are joined to each other with a water film over a range of a width of about 30 mm, for example.
The stack of wet sheets 101 is packaged in a receptacle or container 100 such as a hard case or a package bag having a dispensing opening 100a in a top surface thereof. As the top flap portion 104 of the overlying wet sheet 101 is grasped with the fingers of a user and is pulled out from the dispensing opening 100a, the underlying wet sheet 101 is dragged along with the overlying wet sheet. When the overlying wet sheet 101 is withdrawn, a portion of the top flap portion 104 of the underlying wet sheet 101 protrudes from the dispensing opening 100a to facilitate dispensing the next wet sheet 101.
In this sheet package of this type, however, the dispensing opening 100a has such a smaller width or opening size W11 than a width or as-folded width W10 of the wet sheet 101 as to increase the resistance applied to the wet sheet 101 by the periphery edge of the dispensing opening 100a upon dispensing the sheets. In particular, significantly high resistance is applied to the initial several wet sheets 101 which are located at the upper position of the stack of folded sheets.
Accordingly, the resistance is so significantly high to cause any inconvenience in taking out the initial several wet sheets. In recent years, on the other hand, the wet sheets have been exemplified by water-decomposable sheets which will be dispersed with large quantity of water when disposed of into a flush toilet after use. However, the water-decomposable wet sheets generally have wet breaking strength of 4.9 N or less for a width of 25 mm. Therefore, the water-decomposable wet sheets tend to be broken due to the resistance applied upon dispensing the sheets through the dispensing opening 100a. 
In order to reduce the resistance to be applied by the peripheral edge of the dispensing opening 100a to the wet sheets, there can be conceived means for enlarging the width W11 of the dispensing opening 100a or reducing the width W10 of the wet sheets.
If the width W11 of the dispensing opening 110a is enlarged, however, the sheets packaged in the container 100 are easily dried. If the width W10 of the wet sheets is reduced, on the other hand, the height of the stack of the wet sheets is increased so that the container 100 becomes vertically elongated to cause any inconvenience in transporting and disposing the container for use.
Alternatively, if the number of sheets to be packaged in the container 100 is reduced relative to the capacity of the container 100 to leave a smaller clearance between the uppermost sheet and the dispensing opening, it is possible to reduce the resistance to be applied by the peripheral edge of the dispensing opening 100a when several uppermost sheets are to be taken out. In this case, however, the container 100 is excessively large in comparison with the size of the stack of folded sheets. In the case where the sheet package is formed of the package sheet, it is difficult to continuously automatically package the stack of folded sheets while leaving the clearance (or space) inside the container 100 upon enveloping the stacked sheets with the package sheet.
The present invention has been worked out in view of the shortcoming in the prior art set forth above. It is therefore an object of the present invention to provide a sheet package which allows sheets to be pulled out with a low resistance applied by the peripheral edge of a dispensing opening of a receptacle or a soft package bag without reducing the width (as-folded width) of a stack of folded sheets, without enlarging the width of the dispensing opening, and without leaving an excessive clearance within the receptacle or the soft package bag.
According to an aspect of the present invention, a sheet package comprising:
a stack of sheets including a plurality of sheets folded about fold lines and arranged in a vertically stacked configuration;
a receptacle for containing the stack of sheets, the receptacle made of hard or soft material and having a dispensing opening in a top surface thereof;
the stack of sheets including an upper layer of a plurality of sheets located in the vicinity of the dispensing opening, and a lower layer of a plurality of sheets located under the upper layer; and
the width of the upper layer being smaller than that of the lower layer in a direction perpendicular to the fold lines of the sheets.
For example, on the other hand, the width of the upper layer is substantially equal to the width of the lower layer in a direction parallel to the fold lines.
Furthermore, the clearances are left on both sides of the upper layer within the receptacle.
In the structure of the invention set forth above, the width of the upper layer of the stack of sheets is small so that the low resistance is applied by the peripheral edge of the dispensing opening to the sheets upon taking out the sheets of the upper layer. When the sheets of the lower layer are taken out, on the other hand, a clearance (or space) is left between the sheets of the lower layer and the dispensing opening so that the sheets can be taken out with the low resistance.
For example, the individual sheets are wet sheets moistened with water or a solution. The invention is especially effective in water-decomposable sheets having wet breaking strength of 4.9 N or less per a width of 25 mm in the direction perpendicular to the fold lines of the sheets.
The resistance applied to the sheets upon being pulled out is low enough to prevent the sheets from being broken even if the sheets are water-decomposable sheets having low breaking strength.
The sheets of the invention may be either water-undecomposable wet sheets or dry sheets containing no moisture. In the case of employing these sheets, the resistance to be applied by the peripheral edge of the dispensing opening can be also reduced upon taking out the sheets to be effective in easily withdrawing the sheets.
For example, the individual sheets are folded to define a top flap portion and a bottom flap portion, and interfolded in such a manner that the top flap portion of an underlying sheet lies on the bottom flap portion of an overlying sheet so as to protrude a portion of the underlying sheet from the dispensing opening when the overlying sheet is withdrawn.
In the invention, however, the top and bottom portions of the overlying and underlying sheets may not be overlapped and joined via an overlap portion so that a portion of the underlying sheet is not protruded from the dispensing opening when the overlying sheet is withdrawn.
On the other hand, the number of times of folding the sheets located in the upper layer may be larger than the number of times of folding the sheets located in the lower layer.
It is preferable that the number of the sheets of the upper layer is not less than two, and is also one half or less of a total of the sheets of the upper layer and the lower layer. More preferably, the width of the upper layer is 40 to 90% of the width of the lower layer in the direction perpendicular to the fold lines of the sheets.